Multiple signaling system



July 25, 1933- c. w. HouGH MULTIPLE SIGNALING SYSTEM 3 Sheets-Sheet lFiled Dec. 27, 1930 July 25, 1933. C;l w A HQUGH 1,919,888

MULTIPLE S IGNALING SYSTEM Filed Dec. 27, 1930 :5 Sheets-sheet 2INVENTOR Clin t0n, W Halli/IL.

BY WSEMY N July 25, 1933.

c. w. Houcal-l MULTIPLE SIGNALING SYSTEM 3 Sheets-Sheet 3 Filed Deo. 27,1930 IT .mhls o WM nu 'Hf Il .mhngvwo INVENTOR l i12 fon W Hough.

c 'Mu-A4 g ATTORNEY siste in providing u multiple signaling sys- 1 1nuiltiple sign sling Patented `July 25, 191313` y CLINTON WALLACE11011111101 11111.11 Yon-K, N. Y., iissIGfNoR 111017111111111 111111310,111e.,

OF NEW YORJQN. HY., A CORPURATXON OF DELAWARE i Y MULTIPLE116111111111116 SYSTEM Appiieliiimi 1111111 December 27, 1930. serialNo. 505,055.

"My invention 'pertains in general to signaling systciuis Vandvspecifieelly relates to si guiding systems` tor siniultiineously`transinitting' 11nd receiving-1:1 'plurality otf111essages orprog-rains.` v ,y 1 1 One oftlie 'objects of niy invention con* terri inwliicli'nieiiiis'are-,provided1to1.' simultaneously trzuisinitting endreeel *111g `inoi'e than one niessugie or progriuil by.c11rr1er1l-iiiotber object Iconsists inproducing` a. systeurfor thesin'iultzuieous *t1i111s1111ss1o11 `end reception of inoiethan oneprogram by `carrier frequency current etonerlrequency `produced by tlieinterruption "of irradiaa tions incident upon pliotosensitive ineens.

A i'urtl'ier object coiiiprises producing 11- stem in' which signalii'iodulzition occu before liigglifrequency oscillation'gen(1111151.11011 y l` accomplish `tlie above desirable obgec'l's 5 in11 novel. signaling system employing liglit triiiisinitter 11ndreceiver;

interrupting uien interrupting 11111111191 ior trzuisniitting and rel`eeiviilg'fi plui'zilii'y olE` programs or messages `bythe .multiplenieduliition oi carrier tre-` queney current nt 11 single-lrequencv.

" :[11 tlie drawings Wliieli accompany 11nd forni i1 part of thisspecificfiition iuidin designate 'which `like re'lei'eiioei'iuiiieiii'ls1 eorreslfionding parte tliroi "rhoutf 1 Fig. l islingiiuniiie "respresentetion ot one embodiment oli tbe multiplesignaling; sysieni oi? "my invention",showing` tlie nt eveletion'o sen'iployed 1n :ny syst-e111; y liig. 18 is `sideelevation, Vpartiallysectioned, ot the" light `interi?uptingi` ineens of ling'. is 1:1-sectioiiel View of 1pl1otoelec tric .Y cell housing :ind a..lyinipliousing ein- "ployed in tlie 111p11111'iit11s ojl lV` n 1 Fig.15111.11 un alternative foi-.111 111i! thev 11r- 'iiiliigenient o'f1311.124; :1nd, 1

the system of `n'iy` invention. 1.' 1,

lii'c'zil "representation of1 In `111y co-pendiiig epplicetioinseriel1111111!` ber 469,725,"iled1 July 22,1980, patentedl November l, 1932,No. 1,886,188 and entitled High frequency,generator and iiiodulzitorf" llieved'isclosed a system iii which the ii`1`-"`V tensities of eplurality of light beeins" iii-e variedVV in accordance with modulatingcui` rents and periodically intercepted at superf audible frequencies byineclienical ineens to produce lnioduleted multi-frequency poly pliesealternating currents. My present invention contemplates providing,`signal trans* inissioii ineens for varying the `intensities oiI ziplurality oiliglit beeins iii accordance with modulating curi-ents 11nd,sequentielly exposingl pliotosensitive devices to these light beams etsuper-audible frequencies to produce' liigli frequency oscillations l ate single frequency wliicli will be modulated. with several `simultaneousmessages `or prof.`

1 grains. ,1 My invention` 'further eonteinpletes providingsignalreception ineens for sequentizilly exposing` other pliotosensitive de!vices to i1 source oli' ii'i-adiations'under control ot tlieaforementioned liigli frequency,`

`oscillations to atleet the selective energizetui'n ,secured to e beseReferringto Fig.. 3ei1otlier mounting ring 5 siinilariiicoiistruction toa'iid-coextensive with the inouiitf ing ring l is positioned on thebracket 7 Wliieli secured to tlie bese 3, `as shown.A

in opaque disli1 -8 interposed between the mounting ring, 1' and 5 endis secured to tlie` ernietureslieit 9 oit' a1 inojtor l-O. The inotoiYl0 is secured to `standards `11 "which ere mounted on tlie besev 3Q .YTwo lainpliousings 121 1nd` are posi tioned upontlieinountiiig ring1 l.rRefer-C ringto Fig. 4l, it will be` seentliet the leinp liousinglZisrsecui'edlto tlie ringl bye liol-` 10117 stud l5 whichextendstlirouglienennu! leislot intlie ring` l and is secured. byfenutV16; A neonglow laiiip 17 is mounted Within alziinp housing 12.11Connection `Wires fromV .the lamp 17 are extended through the hol- ,5 bymeans of a hollow stud 2O extending through an annular `slot in the ring5 and secured by a nut 21. A photoelectric cell 22 is positioned Withinthe housing 19 so that the photosensitive cathode thereof is directedtowards the adjacent neon lamp 17. An-

other photoelectric cell housing 23 similar to the housing 19 is mountedupon the ring 5- adjacent the lamp housing 13 and is prof vided with aphotoelectric cell 24 diagrammatically illustrated in Fig. 1. perturesare provided in both the'photoelectric cell housings and in the lamphousings so that light will be directed fromthe glow lamp containedwithin each lamp housing to the sensitized cathode of theadjacent-,photoelectric cell. 1

The disk 8 is provided.A with an annular series of apertures 25 each ofwhich will permit the 1 passage .of light therethrough. These aperturesare spaced in a manner such that, in the rotation of thedisk 8,only oneaperture` will register with either of the apertures in the housing 12or 13. For eX- ample, in the positionof the disk 3, shown in Fig. 2, oneof the anertures 25 is in register with the Vlamphousing 12 permittinglight to pass to the adjacent photoelectric cell, while light from thelamp housing 13 is entirely cutoff by the disk 8, there be n no one ofthe apertures 25 in register therewith. Rotation of the disk will iermitlight to 'C pass, alternately, from the lamp housings 12 and 13 to theadjacent photoelectric cells.

It will be evident, then, that these photoelectric cells will besequentiallyY exposed to the light rays'emergent from tue lamp housings12 and 13; Y

YThe motor 10 is preferably of themsynchronous type for keepin` in stepwith an alternating current and is adapted to rotate the disk 8 at highspeeds so that the sequential excitation of the photoelectric cellsopposite the lamp housings 12 and 13 will talre place at super-audiblefrequencies.

Fig. 1 diagrammatically represents means for the transmission andreception of multiple programs according to my invention. Referring indetail to Fig. 1', the neon glow lamp V17 is connected vthrough batt-ery28 to the secondary of Va transformer 29. A microphone 30 is connectedthrough battery 31 to the primary of transformer 29.

32 to` theserondary of a transformer 33,

The neon glow lamp 18 is connected through battery release battery tothe primary of the transformer 33. Sound waves incident upon themicrophone 30, acting through the transformer 29,y control the intensityof illumination of the lamp 17 in accordance with the sound waves. @thersound waves incident upon the microphone 34 act through transformer 33to similarly control the intensity of illumination of the lamp 1 8 inaccordance with the sound waves. rl`he microphones 30 and 34, and theirassociated circuits, are representative of diilerent sources ofmodulating currents. According to my invention these sources ofmodulating currents are entirely independent of each other and mayconstitute two distinct program or message channels. t will he obviousthat the illumination intensities of the lamps 17 and 18 could becontrolled Afrom other sources of modulating currents, such as from atelevision scanning system, without departing from the intended scope ofmy invention.

'l`he' photoelectric rcells 22 and 24 are connected to amplifiers 36 and37. The amplifiers 36 and 37 may be any suitable type of conventionalamplifier well'known in the art. 1n the present embodiment of myinvention l employ a multi-stage resistance coupled thermionic ampliier.r1`he output from amplifier 36 is connected to an inductance 33 whilethe output from transformer 37 is connected to inductance 39. Theinductances A33 and 3) form independent primaries of a "than those lfin@within a band above the rate of the interceptions of the disk 8 minusthe modulating frequency range and below the rate of the interceptionsof the disk 8 plus the modulating frequency range. The output from 'thefilter 41 is directed to a transn'iitter 42 which comprises means wellknown in the art for suitably increasing the energy value of highfrequency signaling currents for transmission over distances. ln thepresent embodiment of my invention the output of the transi'i'iitter 42is directed through capacitive couplings 43 to power lines 44. Highfrequency oscillations from the transmitter 42 are therefore impressed,as carrier current, upon the lines 44. The lines 44 are connected at theterminals 45 to a source of commercial alternating current.

Accordingto my invention, I provide neon glow lamps 47 and 48, disl 49,photoelectric cells 50 and 5l, and motor 52, which are similar to theneon glow lamps 17 and 18. the disk 8, the photoelectric cells 22 and24, and the motor 10. These elements are arranged in a mechanicalconstruction similar v15o that :Shawn in rigse, amid 4.1 A highAfrequency `tuner and amplifier is provided Leiaess y ,i reception ofhigh frequency signals substantially within the frequencyrangeftransmitted by the filter 41 and, also, av multi- `stageamplifying Vsystem for the amplifica@ y tion of thesesignals. lilheinput to the tuner y 53 is vconnected through capacitive couplings l 54'to` the, power `lines-44 for the reception of carrier frequency energyfrom `the trans-f g `spectivelyconnected to amplifiers 55 and 56.

i The amplifiers `55 and 56 aresimilar in lcon-` struction to ampliers36` and 37; VThe out-V put `of the amplifiers 55 and 56 are directed ftothe demodulation device 57 and theV de- .inodulation device 58,1respectively. "The de-V modulation devices 57and 58 eaclicomprise "avacuum tube-detector systeniwell known initheart for demodul'ation ofthe'modulated high frequency energy.` rlhe output of the.demodulationdevices 57 and 5,8 is

` vdirected to two :loud speakers 159 land 60, re-

former 65, the primary of which isffconnect-` spectively, which comprise:means for translatingelectrical signaling energy into'equivaientacoustical enelgyi Fig. 5 representsan alternativemethod of In thisarrangement two neonlamps 61 and q G2 are positionedwithin,an'elongatedlamp` housing 68.4 The neon lamp 611s connected throughbattery @4to thesecondary of transed througha battery toimicrophone 67.

The neon lamp`62 is connected to batteryl`68 and is maintained lat "asteady `illumination A intensity.` The intensity` of illumination*`preduced by, thelampl is varied in acy. system for the effective)transmission and, `reception of simultaneous programs, Ormesj sages,isasfollows:`

cordaneefwithl modulating currents y under C control of fthe microphone67. Thephotoelectric cell 22is, therefore, Vunder.` control oftheadditive .intensities of the -twolamps (i1 land .62. Theintensity yofthe lamp 62" servestolbias the operation ofthe 'photo' electric cell 22MSuch an arrangement for modulationv may befveryfdesirablefor someYpurposes, such ,as `when it is'desired to modulate upon a higher {part"of the character-` isticA curve of .the photoelectric ,cells i Theoperation `of mymultiple signaling Sound lwaves, comprising a program or`message, impinging upon the microphone `d0 fact through 'the`transformer `29` to controll "i theintensity? ofthe "illuminationiofthe lamp At the same time, other sound waves comprising: a differentprogram or message and :impingmg upon the microphone 34fact throughthetransformer 33 'tocontrol the intensity'of theillumination of thelamp 18. 'The motorlO is madetorrotate the disk 8 at ya constant highspeed wherebythephotof h .electric cells 22 and-24 are alternately, orV

sequentially, exposedtothe lamps 17 and 18,

respectively", q at Asuper-audibleI i frequencies,V

Each of the photoelectric cells 22 and 24 will then `receive a. seriesof light impulses, :the illumination intensityV as before explained.

Y inductances 38 and789 alternately act to induce, inhthe`inductance.40,` electromotive forces `corresponding to the sequence ofmodulatedimpulses from the two amplifiers 86.and87.p'l`he-filter 41substantially at-` tenuates all frequencies other` than those desiredand eliminates `harmonics and other objectionable extraneous` frequencyeffects. The transmitter42 increases the energy `value.` offtheoutputfrom thefilter 41 for transmission,through 'the l capacitive couplings,43,v over the power lines 44. Y modulating illumination intensitywhich" differs frontthatshown in-Fig.` 1" inV thata l source `of biasingillumination isprovided in addition'to the modulatedv light source. f

` The transmitted high frequency currents are directed `from thecapacitive `coupling cillations which are `received and amplified by thehighV frequency'tuner andamplifier 53@ .'llhemotor 52,7{being connectedthrough `:thepowerf1inesj44 to the same source `of *alternating currentwhich supplies the ,i

motorlO, will rotate the disk 49 at sub..

stantiallyi the same speed as the disk It`V will,v Vof course, be`understood that` the motors 10 and 52 are inotnecessarily conlnectedito the same source of .current supply but maylbeconnec'ted toindependentsources Y of currentlsupply and synchronized byother i meansVwell known in the art.`

exposes the photoelectric cells"50 and 5.1 to

the effects ofirradiations from the lamps 47 The disk 49,rotating atahighspeedin y and 48,4 respectively;` .Thelamps 47 and 48, Y beingconnected ,in series withthe .output of tl1e`7high frequency" tuner andamplifier 53,

`have substantially equal illumination intensities at all times.However, `1 the `disk 49 sequentially `exposes the photoelectric cells50 and lfto the lamps 47 and 48 so that the intensityof the `lightimpulses incident upon. vthe ,photoelectric .cells 50 and 51 willrespectively correspond 1 to fthe, intensity of the kas light impulsesincident upon the photoelectric cells 22 and 24. These highl frequencylight impluses willV produce photoelectric currents in the photoelectriccells'() and 5lv which, when respectively amplifiedby the amplifiers 55and 56, and respectively detected by the deinodulation devices 5,7 and58, will cause the loud speakers 59 and 6() to reproduce, in efli'ect,the sound waves respectively incident upon the microphones 30 and 34.A Y

In Fig. 6, curve graphicallyrepre sents, for a'given time interval,xtheamplitude of the modulating current 'Linder control of the microphone 30forY typical acous tical conditions during a program. The curve Bis agraphical representation, for the same time intervahof the amplitude ofthe modulating current under? controlof the microphone 34 for typicalvacousticalconditions of a different program. VThe curves- A71 and A2graphic-ally represent the theoretical upper and lower` side bandstransmitted by the high frequency carrier current produced according tomy system under control of the modulating current ,A, while the curvesB1 and B2 represent the theoretical upper and lower sidebandstransmitted by the high frequency carrier current producedaccording to my system underconi trol of the modulating. current Bz Thefrequency of the carrier current is Ysufficiently highso that the timeintervals `between the high frequency wave peaks for a particular sideband, such as the difference between f2 and 151 for sideV bande, areconsiderably` 'less than any frequency audible to the human ear. Forexample, the carrier frequency used in the present embodiment of `mysystem could be of the order of 30,000

cycles per second` which wouldmake the time interval between t2 andV t1equalto one.fifteenth-thousandth Vof asecond. t 'lhe effective frequencyofthe carrier foreach modulating' current is fifteen kilocycles, whilethefactual frequency of the carrier current isrthirty kilocycles.`However, the actual Y frequency band necessary for the transmission ofboth the modulating currents A and Bn-is'equal to the frequency ofthercarrier current plus' twice the fre quency rangeA Within vwhich themodulation occurs. "lhat is, the actual frequencyvrange requiredaccording to my system is substantially the saine as ifbutone-modulating current, comprising the upper and lower side bands,wasbeing transmitted bythe single carrier frequency, v lt will beobvious that, cy using higher frequencies foi-'the carrier current, morethan two programs can be, in effect, simultaneously transmitted and jreceived according to 'my'inventiou It is, therefore, to be understoodthat the present embodiment of my invention, showing meansfortransmitting and receiving two programs, is'k purely arbitrary andthat the number 4of transmitted and received programs canbe increasedifdesired. 1t will also be obvious that the aperture disks used in ymysystem may be arranged so that several light impulses in succession aregiven to each `photoelectric. cell `so that several wave `peaks insuccession are modulated by one modulating current and then anothergroup of wave peaks are'inodulated by a different modulating current.

lt will now be apparent that I have provided a novel signaling systemfor the transmission and reception of multiple messages or programswhich offers many advantages in its use, principal among which isconservation of frequencie. Although l have shown a preferredVembodiment of my multiple signaling system itis, of course,conte1nplated that changes therein will readily occur to those skilledin the art lbut which will not depart from the intended scope of myinvention. l do not, therefore, desire to limitinyself yto the foregoingexcept insofar as may be pointed. out in the appended claims. l

'lllfhat l claim as new 'and original and desire to secure by LettersPatent of the United States is:

l, 'multiple signaling system comprising, a plurality of sources ofmodulating current, a group of different sources of irradiations cach ofwhich composed of a plurality of sources one of which is under controlof one of said sources of modulating current, pliotosensitive means,means for sequentially exposing said photosensitive means to said groupof plural sources of irradiatious at super-audible frequencies, other;means for producing irradiations under control of said photosensitivemeans, a plurality of photosensitive devices all of which are commonlyunder control of said last mentioned irradistions, means forsequentiallyexposingsaid last mentioned photosensitive devicesto saidirradiations, and a vplurality of translating devices each of which isunder control ofone of said last mentioned photosensitive devices.

2A multiple signaling system comprising, a plurality of sources ofmodulating current, a pluralityv of sources of light cach of whichconsists of apair of sources one of which is underccntrol of' one ofsaid soul of modulatingcurrent,.a group of photoelectric cells, adisk'interposed. between said sources light andsaid photoelectric cellsand .having apertures for sequentially eX- posing said photoelectriccells to said pairs ofl sources of light, means for rotating said disk,means vfor producing irradiations underv control of said photoelcctriccells, another group of pho'toelectric cells, a second disk havingapertures for sequentially eX- posing saidv last mentioned photoelectric`cells to said irradiations',` and a `plurality ,of

electric cells.

translating devices each of Which isunder control of one of saidlast'ineiitioned photo- 3. A multiple signalingsysteni compris-` ing, aplurality of microphones, a plurality `of sourceso'f light eachjof`which consists `of a pair of sourcesv one of which ls'under n control ofone of said microphones, photosensitive means, means for sequentiallyeX- posmg said photosensitive means to said pairs of sources of light atsuper-audible frequencies, means for producing irradiations undercontrol oi said photosensitive Vmeans, a plurality oiphotoelectriccells, a

CLINTON VALLACE HOGH. y

